Debiting full amount after making arrangements

I was in arrears with my 2 getbucks loans, I contacted getbucks and made an arrangement to pay R500.00 on each loan as this was all i could afford. This was confirmed via email. Yet yesterday both loans were debited in full an amount of about R2300.00. I know have no money left to pay rent and buy food! Why did this happen if there was an arrangement in place to only debit 2 x R500.00. How do I survive this month? This is extremely unfair as your mistake has now affected my life